Silicon wafers or sheets may be used in, for example, the integrated circuit or solar cell industry. Demand for solar cells continues to increase as the demand for renewable energy sources increases. One major cost in the solar cell industry is the wafer or sheet used to make solar cells. Reductions in cost to the wafers or sheets may reduce the cost of solar cells and make this renewable energy technology more prevalent. One method that has been investigated to lower the cost of materials for solar cells is the vertical pulling of thin silicon ribbons from a melt that cool and solidify into a crystalline sheet. However, temperature gradients that develop during vertical pulling of silicon sheets may result in poor quality multi-grain silicon. Horizontal ribbon growth (HRG) where sheets are pulled horizontally along the surface of a melt has also been investigated. Earlier attempts include those that employ a gas “showerhead” to provide cooling to achieve the continuous surface growth needed for ribbon pulling. These early attempts have not met the goal of producing a reliable and rapidly drawn wide ribbon with uniform thickness that is “production worthy.” Radiative cooling of a silicon melt has been proposed as an alternative method of forming crystalline silicon. However, a problem arises because radiative cooling by itself may not provide sufficiently rapid removal of heat to properly crystallize a silicon sheet.
It is with respect to these and other considerations that the present improvements have been needed.